Effect of choice of recovery patterns on handrim kinetics in manual wheelchair users with paraplegia and tetraplegia

Make an impact: going full circle together

Sport diversification provides opportunities for individuals to develop physical literacy, establish a growth mindset, become more agile in varied environments, and develop robust strategies to improve performance. One could say the same for biomechanists, who study the control and dynamics of human movements in the context of sport. Through the lens of sport, we have focused on the ongoing interaction between the nervous system, musculoskeletal system, and the environment by using integrated experimental and modelling approaches to study well-practiced, goal-directed tasks in controlled laboratory and realistic field settings. By integrating multiple sources of information in real time to provide timely, relevant, usable, and easy to understand (TRUE) feedback during skill acquisition, we have found these resources also support learning and opportunities for self-discovery of proficiencies by coaches and athletes. Managing multimodal data acquired with emerging technological advances has also benefited from the use of FAIR data management principles, where data are findable, accessible, interoperable, and reusable. By listening, clarifying goals, and exploring together with coaches and athletes, we can bridge the gaps between what we know and what we do.

Augmented feedback for manual wheelchair propulsion technique training in a virtual reality simulator

BACKGROUND

Motor learning of appropriate manual wheelchair propulsion is critical, as incorrect technique elevates risk for upper extremity pain. Virtual reality simulators allow users to practice this complex task in a safe and realistic environment. Additionally, augmented feedback (AF) may be provided in order to optimize learning. The purpose of this study was to investigate the effects of providing AF with various delivery schedules on motor learning and transfer of this skill to over-ground propulsion.

METHODS

Thirty healthy young adults were randomly assigned to three groups. During a virtual reality propulsion training session, the high-frequency AF group received AF in the form of knowledge of performance throughout all propulsion training; the faded AF group received this AF in a faded schedule (high relative frequency of AF early in practice, with relative frequency of AF provision diminishing throughout practice); and the control group underwent training with no AF. Propulsion assessments were performed at baseline and 48 h after practice in both virtual and real environments to measure retention and transfer, respectively.

RESULTS

Compared to the control group, both feedback groups exhibited significant improvements in contact angle and push frequency in both environments after training. Small, non-significant between-group differences were also found between the high-frequency and faded feedback groups.

CONCLUSION

Virtual reality training is an effective learning intervention for acquisition, retention, and transfer of appropriate manual wheelchair propulsion technique when such training includes AF regarding propulsion biomechanics.

The relationship between the hand pattern used during fast wheelchair propulsion and shoulder pain development

Up to 84% of manual wheelchair users (MWCU) with spinal cord injury experience shoulder pain, which is correlated with shoulder adductor weakness in this population. Modeling studies have shown weak shoulder adductors lead to compensations from the deltoid and rotator cuff muscles during propulsion, which may lead to altered propulsion mechanics. However, the role recovery phase hand pattern has in pain development is unclear, as each hand pattern is associated with unique mechanics and different levels of muscle demand. Previous research found no correlation between hand pattern and shoulder pain at self-selected speeds. However, fast propulsion may exacerbate poor mechanics caused by shoulder muscle weakness, which may reveal those at risk for pain development. The present study evaluated whether the hand pattern used during fast wheelchair propulsion is correlated with shoulder pain. We also assessed whether shoulder adductor strength was correlated with hand pattern. Fast propulsion data from two subsets of MWCU were analyzed at three time points (baseline, 18 months, 36 months). All participants were pain-free at baseline. Subset 1 compared individuals who remained pain-free to those who developed shoulder pain. Subset 2 compared individuals with chronic pain at follow-up to those whose pain resolved over time. The hand pattern used was not different between groups in either subset. However, more over-rim patterns were correlated with lower adductor strength in Subset 1. These results suggest that although the hand pattern used during fast propulsion is not correlated with shoulder pain, more over-rim hand patterns may indicate weaker shoulder adductors.

Reaction Force Generation and Mechanical Demand Imposed On the Shoulder When Initiating Manual Wheelchair Propulsion and At Self-selected Fast Speeds

Manual wheelchair (WC) users with spinal cord injury (SCI) experience shoulder pain and fatigue associated with their increased reliance on the upper extremity during activities of daily living [1]. We hypothesized that the mechanical demand imposed on the shoulder, represented as resultant shoulder net joint moment impulse, would be greater when initiating manual WC propulsion from a stationary position without momentum than when manually propelling at speed on a level sidewalk. Thirty manual WC users with paraplegia participated. Each individual initiated manual WC propulsion from a stationary position and propelled on a level sidewalk at their self-selected fast speed. Upper extremity kinematics and pushrim reaction forces (RFs) were measured and upper extremity joint kinetics were calculated and compared (a=0.05) between cycle 1, initiated without momentum, and cycle 3 with momentum. Results indicate that multiple factors contributing to the mechanical demand imposed on the shoulder were significantly greater when manual WC propulsion was initiated without momentum than with momentum. Significant differences in resultant shoulder net joint moment (NJM) impulse, push duration, orientation of RF relative to forearm, and resultant average shoulder NJMs during push were observed between momentum conditions. No significant differences in average resultant RF during push were found. These results indicate that mechanical loading of the shoulder during manual WC propulsion differs between momentum conditions; these differences in resultant shoulder NJM impulse during push need to be considered when assessing shoulder load exposure in stop-and-start activities.

Compensatory strategies during manual wheelchair propulsion in response to weakness in individual muscle groups: A simulation study

BACKGROUND

The considerable physical demand placed on the upper extremity during manual wheelchair propulsion is distributed among individual muscles. The strategy used to distribute the workload is likely influenced by the relative force-generating capacities of individual muscles, and some strategies may be associated with a higher injury risk than others. The objective of this study was to use forward dynamics simulations of manual wheelchair propulsion to identify compensatory strategies that can be used to overcome weakness in individual muscle groups and identify specific strategies that may increase injury risk. Identifying these strategies can provide rationale for the design of targeted rehabilitation programs aimed at preventing the development of pain and injury in manual wheelchair users.

METHODS

Muscle-actuated forward dynamics simulations of manual wheelchair propulsion were analyzed to identify compensatory strategies in response to individual muscle group weakness using individual muscle mechanical power and stress as measures of upper extremity demand.

FINDINGS

The simulation analyses found the upper extremity to be robust to weakness in any single muscle group as the remaining groups were able to compensate and restore normal propulsion mechanics. The rotator cuff muscles experienced relatively high muscle stress levels and exhibited compensatory relationships with the deltoid muscles.

INTERPRETATION

These results underline the importance of strengthening the rotator cuff muscles and supporting muscles whose contributions do not increase the potential for impingement (i.e., the thoracohumeral depressors) and minimize the risk of upper extremity injury in manual wheelchair users.

Shoulder pain and jerk during recovery phase of manual wheelchair propulsion

Repetitive loading of the upper limb due to wheelchair propulsion plays a leading role in the development of shoulder pain in manual wheelchair users (mWCUs). There has been minimal inquiry on understanding wheelchair propulsion kinematics from a human movement ergonomics perspective. This investigation employs an ergonomic metric, jerk, to characterize the recovery phase kinematics of two recommended manual wheelchair propulsion patterns: semi-circular and the double loop. Further it examines if jerk is related to shoulder pain in mWCUs. Data from 22 experienced adult mWCUs was analyzed for this study (semi-circular: n=12 (pain/without-pain:6/6); double-loop: n=10 (pain/without-pain:4/6)). Participants propelled their own wheelchair fitted with SMARTWheels on a roller dynamometer at 1.1 m/s for 3 min. Kinematic and kinetic data of the upper limbs were recorded. Three dimensional absolute jerk experienced at the shoulder, elbow and wrist joint during the recovery phase of wheelchair propulsion were computed. Two-way ANOVAs were conducted with the recovery pattern type and shoulder pain as between group factors.

FINDINGS

(1) Individuals using a semi-circular pattern experienced lower jerk at their arm joints than those using a double loop pattern (P<0.05, η(2)=0.32)wrist;(P=0.05, η(2)=0.19)elbow;(P<0.05, η(2)=0.34)shoulder and (2) individuals with shoulder pain had lower peak jerk magnitude during the recovery phase (P≤0.05, η(2)=0.36)wrist;(P≤0.05, η(2)=0.30)elbow;(P≤0.05, η(2)=0.31)shoulder.

CONCLUSIONS

Jerk during wheelchair propulsion was able to distinguish between pattern types (semi-circular and double loop) and the presence of shoulder pain. Jerk provides novel insights into wheelchair propulsion kinematics and in the future it may be beneficial to incorporate jerk based metric into rehabilitation practice.

The influence of speed and grade on wheelchair propulsion hand pattern

BACKGROUND

The hand pattern used during manual wheelchair propulsion (i.e., full-cycle hand path) can provide insight into an individual's propulsion technique. However, previous analyses of hand patterns have been limited by their focus on a single propulsion condition and reliance on subjective qualitative characterization methods. The purpose of this study was to develop a set of objective quantitative parameters to characterize hand patterns and determine the influence of propulsion speed and grade of incline on the patterns preferred by manual wheelchair users.

METHODS

Kinematic and kinetic data were collected from 170 experienced manual wheelchair users on an ergometer during three conditions: level propulsion at their self-selected speed, level propulsion at their fastest comfortable speed and graded propulsion (8%) at their level self-selected speed. Hand patterns were quantified using a set of objective parameters, and differences across conditions were identified.

FINDINGS

Increased propulsion speed resulted in a shift away from under-rim hand patterns. Increased grade of incline resulted in the hand remaining near the handrim throughout the cycle.

INTERPRETATION

Manual wheelchair users change their hand pattern based on task-specific constraints and goals. Further work is needed to investigate how differences between hand patterns influence upper extremity demand and potentially lead to the development of overuse injuries and pain.